multiselectable dropdown

I'm a newbie in AJAX. I have found a code in the web that uses AJAX and PHP (withjavascripts). It works well but i want to have a multiselectable dropdown. How can i retrieve the value of the multiselctable dropdown thruogh its javascript???

function stateChanged()
{
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
{
document.getElementById("txtHint").innerHTML=xmlHttp.responseText //txtHint is the name of the div that can be replaced by the output of php file
}
}

Take a look at this post. It loops through all the options of a select box and checks for those which are selected. You can then construct a query string based on that.

For eg. if you have a select box name "selBox" from which you have selected two options "one" and "two", your query string should look like: url += "&selBox=one&selBox=two" ; Here one and two would come from the snippet I just pointed you to.

Yes, there are many libraries out there which do this but many people are against using libraries which result in a visible bloat. Implementing our own serialize function or by using the functions from one of the existing libraries in a separate JS file would be much more feasible.

Yes, there are many libraries out there which do this but many people are against using libraries which result in a visible bloat. Implementing our own serialize function or by using the functions from one of the existing libraries in a separate JS file would be much more feasible.

There is really no bloat in mootools. I think the whole lib compressed is about 4k. You can just get part of the library that does the serialization. That would be even less, around 2-3k. Most libraries have something around these lines.

You don't get much learning from using libraries though. Implementing your own give you a much better understanding of the solution.

I have a 2d matrix with dimension (3, n) called A, I want to calculate the normalization and cross product of two arrays (b,z) (see the code please) for each column (for the first column, then the second one and so on).
the function that I created to find the ...

I'm working in Excel to extract content of a table from a web page and populate Excel sheet cells with it. I'm trying to extract data from a table that gets loaded to a web page after show results method gets called. I have an error that says "Run-time error ...